Electric heating apparatus



J. LIGHTFDOT ELECTRIC HEATING APPARATUS Filed Jan. 15. 1324 m w m m Patented Nov. 11, 1924.

UNITED STATES PATENT OFFICE.

JOHN LIGHTFOOT. 0F IMANCHESTER, ENGLAND.

Application filed January 15, 1924.

To all whom it may concern:

Be it known that I, JOHN LIGHTFOOT, a subject of the King of England, residing at Manchester, Lancashire, England, have inventedcertain new and useful Improvements in Electric Heating Apparatus, of which the following a specification.

This invention is for improvements in or relating to electric heating apparatus and has forrits main object to provide a constructionof-heating apparatus of extended form which shall be more economical in use than those more compact constructions at present obtainable.

As is well known in the usual electricstove the heating-wire is massed by coiling an arrangement of the length of coiled wire so that it is located, in acomparatively small area whereby the heating effect is restricted to some one or more points in a room where the stove or stoves are located.

Various constructions of electrical heating units have also been proposed. For example, it has been proposed to fit into an outer metal tube a solid core of insulating material in which longitudinal tubular ducts were provided for the reception of resistance wires. The cross-sectional area of each of these ducts was, however, quite small in relation to the total cross-sectional area of the core, for example one-thirty-sixth part thereof, and their walls were in places relatively thick. Also, such units were intended to be employed singly.

An important object of the present invention is to provide a heating apparatus in which the wire shall be extended so that the one heating device is distributed over a large part of the room. For this purpose the heating-wire, which may be a straight length ot'wire, is enclosed in a tube which can be carried right round the room, say over the wainscctting, but considerable difficulty' has been found inproviding a suitable insulation for. the wire in this extended form; the present invention provides improvedmeans for so insulating such a W1re.--

Accordingto an important feature of this invention-an electric heating apparatus comprisesin combination a plurality of outer metal tubes connected together to form a continuous tubular passage, liner sections in said passage in the form of an inner insulating tube f Whose throughway is sub-divided ELECTRIC HEATING APPARATUS.

Serial No. 686,446.

longitudinally (for example by radial partitions) into at least two longitudinal chambers, and an electrical conductor or conductors traversing the liner from one end of said passage to the other.

Preferably, the said liner is subdivided longitudinally into separate hollow elements each to entirely surround a conductor.

Conveniently, the tubular passage aforesaid is closed at one end by a cap, which may have an electrically insulating lining (for eXa-mple of mica), and is provided at its other end with a mounting which carries-a plug of electrically insulatin material with electrical junction devices, e ectrically'c'onnected each to an end of said conductor 01' conducto-is.

The plug and junction devices referred to in the preceding paragraph may be in the form of awall-plug.

The invention also provides an electric heating unit comprising in combination with an outer metal tube, a liner in the form of an inner insulating tube whose throughway is sub-divided longitudinally into at least two longitudinal chambers, the internal maximum transverse dimension of each of which chambers measured at right-angles to its length is large in relation to the thickness of the wall of the chamber at its thickest part (for example is at least equal to the thickness of the wall of the chamber at its thickest part), and an electrical conductor or conductors traversing said inner tube.

The said liner may consist of an electrically insulating and heat resisting tube of cross-section conforming substantially to a circle, or to a secto-rof acircle, so that when grouped together they will lit the outer tube.

Several embodiments of the invention will now be described with reference to the accompanying drawings, of which;

Figure 1 is a longitudinal elevation partly in section showing one form' of heating unit according to the invention,

Figure is a section on the line 22 of Figure 1,and t Figure 3 is a diagrammatic representation illustrating one method of assemblingfa number of lengths of the inner t'ub'e ele ments;

Figures 4, 5 and 6 show modified forms of inner tubes; i

Figure 7 a plan viewof an extended form of heating apparatus according to the invention arranged round the walls of a room, and

Figure 8 is an elevation of an electric radiator according to the invention.

Like reference numerals indicate like parts in each of the figures.

Referring first to Figures 1 to 3, a metal outer tube 10 has within it a liner in the form of an inner insulating tube consisting of two series of elements 11. whereby the throughway of the liner is sub-divided longitudinally into two longitudinal chambers 12. These elements may be formed of porcelain or other convenient heat-resisting and insulating material, and are substantially semi-circular in section, each having a throughway 12, and each of a convenient length. They are positioned within the tube with their flat faces at the two ends of the outer tube adjacent one to the other, and each element constitutes a liner section. A conductor 13 is threaded through the throughway 12 in one series of elements and back through the throughway 12 in the other series of elements. The conductor 13 which may be coiled-or not, is electrically connected at its ends to plugs .11 carried by a block of insulating material 15. This block of insulating material 15 is fixed in the small end of a two-diameter metal housing lii which has its larger end screwed to the end of the metal outer tube 10. A socket connector 17, which is provided with a screwed ring 18 for engagement with the smaller end of the housing 16, detachably engages the plugs 14. The other end of the metal tube 10 has screwed upon it a metal cap 19, which has a lining 20 of mica or other convenient insulating material. This cap 19 may be screwed up tightly in such a manner as to clamp the elements 11 and pre-- vent longitudinal movement thereof. The mica lining 2O prevents contact of the con ductor 13 with the metal cap 19. As shown in Figure 2, the internal maximum transverse dimensions of each of the chambers 12 measured at right-angles to its length is large in relation to the thickness of the wall of the chamber at its thickest part. 111 other words each chamber 12 isof relativel large cross-sectional area to provide large spaces for heated air. hen more than two chambers are provided in the liner, the said dimension is at least equal to thethick ness of the wall of the chamber at its thickest part. Obviously, if the outer tube 10 is not too long only two elements 11 need be provided each extending from end to end of the tube 10 to form a heating unit.

It will be seen that this construction constitutes an electric heating unit which can readily be built up into electric heating apparatus of extended form of any desired length. In such apparatus the elements 11 end by unions 110 and arranged round the walls of a room indicated inebroken lines, for'example just above the wainscotting. Another form of extended electric heating apparatus of the kind described is illustrated in Figure 8 which shows an electric radiator 120 comprising outer tubes 10 having each an insulating liner of the kind described above for receiving resistance wires.

It is obvious that more than two series of elements n'iight be used, for example, the conductor might extend throughout the length of the outer tube 10 four times'in which case four series of elements 111 having a section formed substantially as a quadrant of a circle would be used, as shown in Figure 4. Likewise, for a polyphase supply one conductor and one series of elements might be used for each phase, in which case the elements might have the shape shown at 112 in Figure 5. Alternatively. a series of single tubular members whose throughways are sub-divided longi tudinally by a suitable number of partitions may be used; Figure 6 shows such a single member 113 having a partition dividing it into two ducts.

- It will be understood that the above description is given by way of example only and that many modifications may be made without departing from the scope of this in vention. For example, the liner may be made of some other material than porcelain, such as earthenware or magnesium silicate, and the junction device at the one end of the outer tube may take the form of a concentric wall-plug.

What I claim as my invention and desire to secure by Letters Patent is:

1. Electric heating apparatus comprising in combination a plurality of outer metal tubes connected together to form a continuous tubular passage. a liner in said passage in the form of an insulating tube whose throughway is sub-divided longitudinally into at least two longitudinal chambers, and an electrical conductor traversing the liner from one end of said passage to the other.

2. Electric heating apparatus comprising in combination a plurality of outer metal tubes connected together to form a continuous tubular passage, a liner in said passage in the form of an insulating tube whose thrbi'ighway' is sub-divided longitudinally by radialpartitions'into at least two longitudinal chambers; and anelectrical conductor traversing the" liner in each chamber from one-end ofsaid passage to the other.

8. Electric apparatus comprising in combination a plurality of outer metal tubes connected together to fornr a continuous tubular passage, liner sections in said passage-in the form of an insulating tube whose througliway is sub-divided longitudinally into at least twolongitudinal separate hol low elements each constituting a chamber, and an electrical conductor traversing the elements from one end of said passage to the other.

4. Electric heating apparatus comprising in combination a plurality of outer metal tubesconnecte'd together'to form a tubular passage, an insulating liner sub-divided longitudinally into separate hollow elements in said passage, which elements have each a cross-section which is substantially asector of a circle, and an electrical conductor traversing the liner in said elements from one end of said passage to the other.

5. Electric heating apparatus comprising combination a plurality of outer metal tubes connected together to form a continuous tubular passage, an insulating liner subdivided longitudinally into separate hollow elements in said passage, which elements are arranged in a plurality of rows of elements extending along said passage with the joints between the elements in one row staggered in relation to the joints between the elements in another row, and an electrical conductor in said elements traversing the liner from one end of said passage to the other.

6. Electric heating apparatus comprising in combination a plurality of outer metal tubes connected together to form a continuous tubular passage. a liner in said passage in the form of an insulating tube Whose throughway is sub-divided longitudinally into at least two longitudinal chambers, one or more electrical conductors traversing said chambers from one end of said passage to the other, a cap closing the tubular passage at one end, plug of electrical- 1y insulating material at the other end of said passage, and electric junction devices on said plug each for connection to a conductor in said passage.

7. Electric heating apparatus comprising in combination a plurality of outer metal tubes connected together to form a continuous tubular passage, a liner in said passage in the form of an insulating tube whose throughway is sub-divided longitudinally into at least two longitudinal elements, an electrical conductor traversing the liner from one end of said passage to the other, a cap closing the tubular passage at one endl and a junction device of the wall plug type forclosing'thetubular passage of the chamber at its thickest part, and'an' electrical conductor or conductors trav'ers mg saidunner tube.

In electric heating apparatus, the combination of an outer metal tube, a liner thereforin the'form of an inner insulating tube whose throughway is sub-divided longitudinally into at least two longitudinal chambers, the internal maximum transverse dimension of each of which chambers measured at right-angles to its length is at least equal to th thickness of the wall of the chamber at its thickest part, and one or more electrical conductors traversing said inner tube.

10. In electric heating apparatus, the combination of an outer metal tube, and an inner heat-resisting insulating tube constituting a liner therefor whose throughway is subdivided into at least two longitudinal chambers each extending from one end of the metal tube to the other, substantially as and for the purpose described.

ll. in electric heating apparatus, thev combination of an outer metal tube, and an inner heat-resisting insulating tube constituting a liner therefor whose throughway is sub-divided longitudinally into at least two separate hollow elements having each a cross-section which is substantially a sector of a circle, and extending each from one end of the metal tube to the other, substantially as and for the purpose described.

12. The combination of an outer metal tube, and an inner heat-resisting insulating tube constituting a liner therefor whose throughway is sub-divided into at least two longifiidinal chambers, cap, having an electrical insulating lining, closing one end of the outer tube, and a mounting at the other end of the outer tube, a plug of elec trical insulating material in said mounting, and electrical junction devices carried by said plug for electrical connection to conductors in the liner.

13. An electric heating apparatus of extended form comprising in combination a plurality of outer metal tubes connected together to form a rectangular structure containing a continuous tubular passage whereof some parts are connected at right angles to other parts, a liner in said passage in the form of an insulating tube whose throughway is sub-divided longitudinally throughout its length into at least two longitudinal chambers, and an electrical sulating refractory tube therein subdivided longitudinally into at least tWo chambers, an electrical heating conductor extending rectilinearly through the said chambers in the inner tube, and electrical junction de vices connected each to an end of said conductor, substantially as described.

16. An electrical heating apparatus COITlprising in combination a metal outer tube, a heat-resisting inner tube subdivided longitudinally into two ducts, an electrical heating conductor extending rectilinearly in said ducts to and fro through the inner tube, and electrical junction devices at one end of the outer tube connected each to an end of said conductor, substantially as described.

In testimony whereof I afiix my signature.

JOHN LIGHTFOOT. 

